The present invention relates to a laser ablation apparatus used for film formation of a superconductor or a ferroelectrics utilized in a thin film device.
One example of a conventional laser ablation apparatus will be explained below.
In the conventional laser ablation apparatus, as shown in FIG. 2, a laser beam 2 having the energy density not less than a threshold value is irradiated on an object 7 to be processed located in a vacuum chamber 5 to fly substance such as particles 19 out from the object 7 and then adhere the substance 19 to a substrate 15 supported by a substrate holder 14. The laser beam 2 is normally irradiated on the object 7 by focusing a short-wavelength pulsed laser beam with high energy density. The laser beam is focused by a lens 3 through a vacuum sealing window 4 onto the object 7. The air in the vacuum chamber 5 is exhausted by a vacuum pump 6.
In such an apparatus, however, parts of the object 7 is heated to high temperature in a short period of time, and then clusters 20 not more than several micron (which is normally called as droplets) are flown out from the object 7. Then, since such clusters 20 are mingled in a thin film formed on the substrate 15, it is difficult to make the thin film flat which is basically required in a thin film device.